Synthesis and characterization of CuII and CoII complexes derived from 2,4,6-tri-(2-pyridyl)-1,3,5-triazine (TPT) by chemical and tribochemical reactions

Four Cu-II and Co-II complexes - [Cu(L-1)Cl-2(H2O)]3/2H(2)O center dot 1/2EtOH, [Cu(L-1)(2)Cl-2]6H(2)O, [Co(L-1)Cl-2]3H(2)O center dot EtOH, and [Co-2(L-1)(H2O)Cl-4]1.5H(2)O center dot EtOH (L-1 = 2,4,6-tri(2-pyridyl)1,3,5-triazine; TPT) - were synthesized by conventional chemical method and used to synthesize another four metal complexes -[Cu(L-1)I-2(H2O)]6H(2)O, [Cu(L-1)(2)I-2]6H(2)O, [Co(L-1)I(H2O)(2)]I center dot 2H(2)O, and [Co-2(L-1)I-4(H2O)(3)] - using tribochemical reaction, by grinding it with KI. Substitution of chloride by iodide occurred, but no reduction for Cu-II or oxidation of Co-II. Oxidation of Co-II to Co-III complexes was only observed on the dissolution of Co-II complexes in d(6)-DMSO in air while warming. The isolated solid complexes (Cu-II and Co-II) have been characterized by elemental analyses, conductivities, spectral (IR, UV-Vis, H-1-NMR), thermal measurements (TGA), and magnetic measurements. The values of molar conductivities suggest non-electrolytes in DMF. The metal complexes are paramagnetic. IR spectra indicate that TPT is tridentate coordinating via the two pyridyl nitrogens and one triazine nitrogen forming two five-membered rings around the metal in M : L complexes and bidentate via one triazine nitrogen and one pyridyl nitrogen in ML2 complexes. In binuclear complexes, L is tridentate toward one Co-II and bidentate toward the second Co-II in [Co-2(L-1)Cl-4]2.5H(2)O center dot EtOH and [Co-2(L-1)I-4(H2O)(3)]. Electronic spectra and magnetic measurements suggest a distorted-octahedral around Cu-II and high-spin octahedral and square-pyramidal geometry around Co-II.